Time-valve for pneumatic railway-signals.



- No. 636,770. Patented Nov. l4, I899.

F. L. Douasou. TIME VALVE ron PNEUMATIC RAILWAY SIGNALS.

(Application filed Oct. 29, 1897.)

(No Model.)

Fig. 1.

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UNITED STATES PATENT OFFICE.

FRANK L. DODGSON, OF ROCHESTER, NEW YORK, ASSIGNOR, BY MESNE AS-SIGNMENTS, TO THE PNEUMATIC RAILWAY SIGNAL COMPANY, OF WEST VIRGINIA.

Tl ME-VALVE FOR PNEUMATIC RAILWAY-SIGNALS.

SPECIFICATION forming part of Letters Patent No. 636,770, dated November14, 1899.

Application filed October 29, 1897. SeriaLNo. 656,857. (No model.)

'To all whom it may concern:

Be it known that I, FRANK L. DODGSON, a citizen of the United States,residing at Rochester, Monroe county, New York, have invented anImproved Time-Valve for Pneumatic Railway-Signals, of which thefollowing is a specification, reference being had to the accompanyingdrawings.

My invention relates to an improved timevalve for pneumaticrailway-signals, which improvement is fully described and illustrated inthe following specification and the accompanying drawings, the novelfeatures thereof being specified in the claims annexed to the saidspecification.

' My invention is represented in the accompanying drawing, in which thefigure is a sectional elevation of a time-valve embodying myimprovement.

The object of this invention is to furnish means by which a valve usedin operating a pneumatic railway-signal may be opened and may be leftopen for a certain length oftime and may be automatically closed at theexpiration of such time. As an illustration, supposingit be required tofill the signal-pipe H in the accompanying drawings to a certaindefinite pressure, this can be done by operating a Valve between thesignal-pipe and the main supply-pipe M and leaving said valve open for adefinite length of time, that time depen ding upon the length and areaof the pipe H. In order to accomplish this result, I employ a cylinderA, having a side'opening J about midway of its length and containing apiston B, that travels up and down in the cylinder and acts when in itslowest position as a weight to close the time-valve I. The piston andthe valve are not connected together but the stem of the valve extendsinto the path of movement of the piston, and when the piston strikessaid stem itcloses the valve, and when the piston is lifted from contactwith said stem the valve may open. The piston and the cylinder have suchrelative proportions that the escape-orifice J is uncovered when thepiston is at either the top or the bottom of the cylinder; but when thepiston is at other positions in its movement in the cylinder the orificeJ is covered by the piston, so that the cylinder is cut off fromconnection with the outer air.

The piston B is adapted to be raised to the position shown in dottedlines in the figure by air under pressure admitted through theoperating-pipe O and the valve D. The valve D is an ordinary three-wayvalve with an ample escape-orifice to the outer air, as usual. Theraising of the piston B high enough to lift it from contact with thevalve I permits the pressure of the air from the main M through thebranch pipe E to raise the valve I, so as to open the port F, throughwhich the air passes into the pipe H. As the piston rises the air in thecylinder above it passes out freely through the opening J, thuspermitting a rapid upward movement of the piston at first and a quickrelease of the valve I. The piston in its further upward movement sooncloses the escape-orifice J, andafter said orifice is thus closed theair passes out freely through a back-pressure checkvalve G at the upperpart of the cylinder. After sufficient air has been admitted, as abovedescribed, by the proper turning of the valve D to raise the piston toits highest position the valve is turned so as to close it, or, ifdesired, the valve may be kept open, and the piston may thus be held inthe upper part of the cylinder and away from the valve I. When thepiston has arrived at the upperend of its travel, it uncovers theescape-orifice J in the side of the cylinder and allows the compressedair below the piston to escape, which permits the piston to drop quicklyuntil the orifice J is again closed. It must be understood that theopening of the Valve D to admit the air to the cylinder is ordinarilybut momentary. After the piston has dropped partly back, as justdescribed, the valve D is turned so as to connect with the outer airthrough its escape-orifice above mentioned, and thereupon the pistonwill descend and the air in the cylinder underneath the piston passesout through the pipe 0 and valve D. The time occupied by the descent ofthe piston B is regulated .by the restricted admission of air into theupper part of the cylinder through the valve K, which may be set so thatthe piston may descend at any desired rate of speed. The cock or valve Kmay be of any usual or preferred type and maybe arranged to be set withany desired amount of opening through it for the said restrictedadmission of air. When the piston B arrives at the end of its downwardmovement, the orifice J is again uncovered, permitting air to passfreely into the upper end of the cylinder, and thus permitting a quickdownward movement of the piston, so that it closes the valve I with someforce by contact with its stem L, and the weight of'the piston holds thevalve I closed against pressure of air from the main E. The stem Lprojects upward from the valve I through a collar N, inserted in theupper end of the tube or valve casing O in the lower cylinder-head P. Ateach end of its travel the valve I seats against a packing ab within thevalve-casing. The port F opens laterally through the valve-casing O andthence extends downward through the cylinder-head, connecting with thepipe II.

The valve D may be arranged to be operated in any suitable way-as, forinstance, by hand or by the passage of a train. As shown in thedrawings, the device is operated by hand, although the valve D may beset at any desired distance from the cylinder A.

It will be noticed that the upward movement of the piston, so far as isnecessary to allow the valve I to be lifted, is a free movement, andthat the movement of the piston through that part of its stroke thatcloses the valve I is likewise a free movement, and that the deviceproduces quick action of the signal-valve I, both for opening and forclosing the air-inlet from the main M to the signalpipe H, permitting atthe same time a definite interval of time to elapse for the closing ofthe valve after the operating-valve D is set to its normal position. Theemployment of the three-way valve for operating this device and thenormal setting of said valve in the position described above rendersaccidental operation of the piston, and consequently of the signal,practically impossible.

I claim 1. In a railway-signal time-valve mechanism, a valve controllingthe signal-pipe, a gravity device normally holding the valve on its seatto close the inlet to said pipe, means for lifting said gravity devicefrom said valve, and automatic means for controlling the rapidity ofreturn of said gravity device to restore said valve to its seat,substantially as described.

2. The combination, with the upright cylinder A, of the piston 13, theescape-valve G, the regulating inlet-valve K, said valve being connectedwith the highest part of the cylin der, the time-valve I having a stemextending into the path of movement of the piston, a pipe connectingwith the cylinder for operating the piston, and a signal-pipe controlledby the time-valve, substan tially as described.

3. In a time-valve for pneumatic railway signals, the combination of acylinder, a regulatable inlet-valve connecting with one end of saidcylinder and an escape device, a piston in said cylinder, a pipeconnecting with said cylinder for operating the piston, a threeway valvecontrolling said pipe, a main supply-pipe, a signal-pipe, a valvedisconnected from said piston and held closed by the weight thereof, andadapted to be raised to open communication between the main supplypipeand the signal-pipe upon the raising of the piston, substantially asdescribed.

4. The combination, in a time-valve for pneumatic railway-signals, ofthe cylinder A, the piston B, a pipe connecting with said cylinder foroperating the piston, the lower cylinder-head having the valve-casing O,the time-valve in said casing disconnected from said piston and havingthe stem L guided in said casing and extending within the cylinder, andsuitable connecting-pi pin g, substantially as described.

5. The combination with the upright cylinder A, of the piston B,escape-valve G, regulating-valve K, time-valve I, inlet-pipe O havingvalve D, the escape-orifice J and suitableconnecting-piping,substantially as described.

FRANK L. DODGSON.

Witnesses:

GERTRUDE C. BLACKALL, S. P. MOORE.

